Video clip 3 - Polymer plasticisation (Part 1 of 2)

Here we can see the principle behind the formation of a polymer scaffold for use in Tissue Engineering and Drug Delivery.

The granular polymer is placed into a high pressure autoclave inside a suitable container. The autoclave is heated and CO₂ is added. Once the critical temperature and pressure of CO₂ is reached the CO₂ becomes supercritical and at this point it can effectively turn the solid polymer into a liquid-like state. This is called plasticisation.

At this point the polymer is liquid-like enough to mix in whatever substance we want, for example, solid or liquid based drugs or enzymes etc. Note we are not heating the polymer until it melts (melting temperature normally >100 ^oC) plasticisation of this particular polymer can be achieved at human body temperature (37 ^oC).

Hence this method using supercritical CO₂ is particularly attractive for processing polymer scaffolds with incorporated temperature sensitive drugs or biological structures.

Video clip 4: Scaffold formation